.\"	$OpenBSD: SSL_want.3,v 1.5 2018/03/27 17:35:50 schwarze Exp $
.\"	OpenSSL 9b86974e Aug 17 15:21:33 2015 -0400
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.Dd $Mdocdate: March 27 2018 $
.Dt SSL_WANT 3
.Os
.Sh NAME
.Nm SSL_want ,
.Nm SSL_want_nothing ,
.Nm SSL_want_read ,
.Nm SSL_want_write ,
.Nm SSL_want_x509_lookup
.Nd obtain state information TLS/SSL I/O operation
.Sh SYNOPSIS
.In openssl/ssl.h
.Ft int
.Fn SSL_want "const SSL *ssl"
.Ft int
.Fn SSL_want_nothing "const SSL *ssl"
.Ft int
.Fn SSL_want_read "const SSL *ssl"
.Ft int
.Fn SSL_want_write "const SSL *ssl"
.Ft int
.Fn SSL_want_x509_lookup "const SSL *ssl"
.Sh DESCRIPTION
.Fn SSL_want
returns state information for the
.Vt SSL
object
.Fa ssl .
.Pp
The other
.Fn SSL_want_*
calls are shortcuts for the possible states returned by
.Fn SSL_want .
.Pp
.Fn SSL_want
examines the internal state information of the
.Vt SSL
object.
Its return values are similar to those of
.Xr SSL_get_error 3 .
Unlike
.Xr SSL_get_error 3 ,
which also evaluates the error queue,
the results are obtained by examining an internal state flag only.
The information must therefore only be used for normal operation under
non-blocking I/O.
Error conditions are not handled and must be treated using
.Xr SSL_get_error 3 .
.Pp
The result returned by
.Fn SSL_want
should always be consistent with the result of
.Xr SSL_get_error 3 .
.Sh RETURN VALUES
The following return values can currently occur for
.Fn SSL_want :
.Bl -tag -width Ds
.It Dv SSL_NOTHING
There is no data to be written or to be read.
.It Dv SSL_WRITING
There are data in the SSL buffer that must be written to the underlying
.Vt BIO
layer in order to complete the actual
.Fn SSL_*
operation.
A call to
.Xr SSL_get_error 3
should return
.Dv SSL_ERROR_WANT_WRITE .
.It Dv SSL_READING
More data must be read from the underlying
.Vt BIO
layer in order to
complete the actual
.Fn SSL_*
operation.
A call to
.Xr SSL_get_error 3
should return
.Dv SSL_ERROR_WANT_READ .
.It Dv SSL_X509_LOOKUP
The operation did not complete because an application callback set by
.Xr SSL_CTX_set_client_cert_cb 3
has asked to be called again.
A call to
.Xr SSL_get_error 3
should return
.Dv SSL_ERROR_WANT_X509_LOOKUP .
.El
.Pp
.Fn SSL_want_nothing ,
.Fn SSL_want_read ,
.Fn SSL_want_write ,
and
.Fn SSL_want_x509_lookup
return 1 when the corresponding condition is true or 0 otherwise.
.Sh SEE ALSO
.Xr err 3 ,
.Xr ssl 3 ,
.Xr SSL_get_error 3
.Sh HISTORY
.Fn SSL_want ,
.Fn SSL_want_nothing ,
.Fn SSL_want_read ,
and
.Fn SSL_want_write
first appeared in SSLeay 0.5.2.
.Fn SSL_want_x509_lookup
first appeared in SSLeay 0.6.0.
These functions have been available since
.Ox 2.4 .
